IPv6 in Linux
Core Technology

IPv6 is the future of the Internet, and it promises many goodies. Discover what your Linux box can do about it today.
IPv4, today's Internet workhorse protocol, offers more than 4 billion IP addresses. This may seem like a lot, but in a world of 7 billion people and every single toaster seemingly wanting an Internet connection, it's actually not. In fact, IANA, the Internet's numbering authority, allocated the last block of IPv4 addresses about six years ago. That doesn't mean there are no spare IPv4 addresses left on the planet – regional operators still have some reserves – but the supply already has been exhausted.
IPv6 comes to the rescue. With 128-bit addresses – that is, about a quadrillion IPs per every human body cell in the world, we'll hopefully be on the safe side for some time. However, IPv6 offers much more than extra bits in the address; it fixes a 35-year irritant of IPv4 operation by allowing the network to function without network address translation (NAT) or DHCP. Moreover, it enjoys being a first-class citizen in your Linux box.
Back to Basics
In general, IPv6 addresses are shown as eight 2-byte, colon-delimited hexadecimal numbers (e.g., fe80:0000:0000:0000:eef4:bbff:fe29:873d). So many numbers are awkward, so a few simplifications are possible. First, you can omit leading zeros: 0001 is the same as 1, and 0000 is the same as 0. Second, you can drop running sequences of all zeros, which are quite common in IPv6 addresses. You can do this only once per address for the longest sequence, though. A double colon shows where zeros were: consider fe80::eef4:bbff:fe29:873d or even ::1, which is just a loop-back address, serving the same purposes as 127.0.0.1 in IPv4. This means a single IPv6 address may have several equally valid representations. If you think IPv6 addresses are more difficult to parse than IPv4, that's true. Luckily, libraries such as glibc handle this for you.
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

News
-
Linux Kernel 6.17 is Available
Linus Torvalds has announced that the latest kernel has been released with plenty of core improvements and even more hardware support.
-
Kali Linux 2025.3 Released with New Hacking Tools
If you're a Kali Linux fan, you'll be glad to know that the third release of this famous pen-testing distribution is now available with updates for key components.
-
Zorin OS 18 Beta Available for Testing
The latest release from the team behind Zorin OS is ready for public testing, and it includes plenty of improvements to make it more powerful, user-friendly, and productive.
-
Fedora Linux 43 Beta Now Available for Testing
Fedora Linux 43 Beta ships with Gnome 49 and KDE Plasma 6.4 (and other goodies).
-
USB4 Maintainer Leaves Intel
Michael Jamet, one of the primary maintainers of USB4 and Thunderbolt drivers, has left Intel, leaving a gaping hole for the Linux community to deal with.
-
Budgie 10.9.3 Now Available
The latest version of this elegant and configurable Linux desktop aligns with changes in Gnome 49.
-
KDE Linux Alpha Available for Daring Users
It's official, KDE Linux has arrived, but it's not quite ready for prime time.
-
AMD Initiates Graphics Driver Updates for Linux Kernel 6.18
This new AMD update focuses on power management, display handling, and hardware support for Radeon GPUs.
-
AerynOS Alpha Release Available
With a choice of several desktop environments, AerynOS 2025.08 is almost ready to be your next operating system.
-
AUR Repository Still Under DDoS Attack
Arch User Repository continues to be under a DDoS attack that has been going on for more than two weeks.